A diary of the first ECOMAR cruise to the Mid-Atlantic Ridge
August 17, 2007
Filed under: Uncategorized — Nikki @ 8:22 am

Despite the excitement building over the past couple of days at the prospect of standing on stable ground again, it was still somewhat of a shock to awake this morning to see land surrounding the James Cook. Any land would be contrast enough to the dark blue swells and white caps that had exclusively composed the horizon for the last month, but the cliffs and woods of western Scotland were a particularly beautiful sight.

Passing Ireland in the early hours of morning, the ship spent the first half of the day sailing up the lower Firth of Clyde toward the Isle of Arran. Under sun and blue skies, and protected from the harsher oceanic winds, the atmosphere on deck was warm and some of the crew took the opportunity for recreational fishing (the technological simplicity of which is even more striking after OTSBs and RMTs). Several jellyfish were caught for David to photograph using a yet simpler technique: slowly lowering large buckets into the water.

An especially captivating display was put on by the northern gannets (Morus bassanus). The sleek, white birds spot their prey while flying 30 to 45 meters above the water’s surface, and, tucking their wings inward to form a distinct “W”, dive at speeds up to 100 km/hour and to depths averaging 20 meters.

Later, the ship’s rescue boat underwent a routine test, providing the chance for a few people to go ashore briefly.

Cleaning and packing efforts intensified today, as most of the labs were emptied of their gear, the floors mopped and the sinks scrubbed for the next scientific party. Specimens fixed in formalin, sensors from the landers and other instruments, and essentially anything else that is to be removed from the ship and sent back to its research institute of origin, was moved into the hanger and onto the aft deck. This was mostly accomplished by dinner, which unfortunately was the last time on this cruise that some of the crew will experience the impressive desserts of chef Lloyd Sutton

The last work that remains to be done is the EK60 calibration, the same process described by Nikki on 15 July. As a quick reminder, this involves lowering a 38.1mm tungsten sphere below the ship, and locating the sphere on each of the five frequencies of the EK60 echosounder. Actual measurements are compared with predictions to identify how earlier EK60 data should be corrected. This calibration is going more smoothly than the session at Bantry Bay in Ireland, due to less attenuation caused by plankton and fish encircling the vessel (causing the sphere’s signal to weaken), but each frequency still requires two hours. Martin Cox, Mike Myers, and Birkir, manning the EK60 console in the main lab, noted a growing number of jellyfish beneath the ship, but as of now calibration continues without serious interruption. And in the morning, after the calibration is completed, we head to port.

Jeff Mashburn
Durham University